In many chemical processes, caustic soda may be required to achieve a chemical reaction, e.g., to neutralize an acid, or buffer pH of a solution, or precipitate an insoluble hydroxide from a solution. One method by which the caustic soda may be produced is by an electrochemical system. In producing the caustic soda electrochemically, such as via chlor-alkali process, a large amount of energy, salt, and water may be used.
Polyvinyl chloride, commonly known as PVC, may be the third-most widely-produced plastic, after polyethylene and polypropylene. PVC is widely used in construction because it is durable, cheap, and easily worked. PVC may be made by polymerization of vinyl chloride monomer which in turn may be made from ethylene dichloride. Ethylene dichloride may be made by direct chlorination of ethylene using chlorine gas made from the chlor-alkali process.
The production of chlorine and caustic soda by electrolysis of aqueous solutions of sodium chloride or brine is one of the electrochemical processes demanding high-energy consumption. The total energy requirement is for instance about 2% in the USA and about 1% in Japan of the gross electric power generated, to maintain this process by the chlor-alkali industry. The high energy consumption may be related to high carbon dioxide emission owing to burning of fossil fuels. Therefore, reduction in the electrical power demand needs to be addressed to curtail environment pollution and global warming.